In 2012, minority drivers made up 34 percent of all Rockford traffic stops. Minorities, though, were 28.48 percent of the driving population, according to data gathered by public safety firm Alexander Weiss Consulting LLC.

A new report from the American Civil Liberties Union says racial bias still persists during consent searches done by police during traffic stops.

The ACLU reviewed data from the Illinois Traffic Stop Study for 2013, which showed black and Latino drivers are more likely to be asked for consent to search their vehicles for contraband than white drivers.

Across Illinois, black and Latino drivers are nearly twice as likely as whites to be asked to consent to searches during a routine traffic stop, according to the ACLU. Yet white drivers are 49 percent more likely than African-American motorists and 56 percent more likely than Latino drivers to have contraband discovered during such a search.

The fact that more black and Latino drivers are searched but fewer are found in possession of illegal drugs or weapons is evidence to some that police are searching minority drivers without cause.

“We see that these troubling signs of racial bias have persisted for a decade in many of our larger police agencies without any response — that has to end,” said Adam Schwartz, senior legal counsel for the American Civil Liberties Union of Illinois, in a news release.

The ACLU's report also put a spotlight on the practice in Rockford. The report states that black drivers in Rockford were 69 percent more likely than white drivers to be asked for consent to search their cars, even though white motorists were 67 percent more likely than African-American motorists to be found with contraband.

In June, the Register Star published an in-depth report on racial profiling during traffic stops. That report, which studied traffic stop data from 2003-2012, had similar results to the data released today by the ACLU.

The Register Star's report showed that black and Latino motorists are pulled over more often than white drivers. It's a phenomenon that can be attributed to a larger police presence in high-crime areas, which also have higher populations of blacks and Latinos. Police officers make more traffic stops in high-crime areas in an effort to make arrests for more serious violations, such as possession of drugs or weapons.

“In my tenure, I think we’ve had two complaints of racial profiling,” Rockford Police Chief Chet Epperson said in the June story. “They’ve both been vetted out internally and found not to be true.”

About 43 percent of the traffic stops Rockford police made in 2013 were of minority drivers, according to the latest Illinois Traffic Stop Study, which was released in July. Minority drivers make up about 35 percent of the driving population, according to the report.

Minority drivers were 23 percent more likely to be pulled over in 2013, up slightly from 21 percent in 2012, according to the report. The peak came in 2010, when minority drivers were 63 percent more likely to be stopped.